Liquid detergent compositions

ABSTRACT

A PHASE-STABLE POURABLE, HEAVY-DUTY, LIQUID DETERGENT EMULSION COMPOSITION WHICH DOES NOT EXHIBIT A SUBSTANTIAL CHANGE IN VISCOSITY ON STANDING COMPRISING A NONIONIC SYNTHETIC DETERGENT, AN ALKALI METAL PYROPHOSPHATE, A COMBINATION OF A FIRST STABILIZER WHICH IS A HYDROLYZED LINEAR COPOLYMER OF ETHYLENE AND MALEIC ANHYDRIDE AND A SECOND STABILZER WHICH IS A HYDROLYZED CROSS-LINKED COPOLYMER OF ETHYLENE AND MALEIC ANHYDRIDE, AND THE BALANCE SUBSTANTIALLY WATER.

United States Patent 3,629,125 LIQUID DETERGENT COMPOSITIONS ThomasAquinas Payne, Jr., Teaneck, and Warren Eric Olson, Verona, N.J.,assignors to Lever Brothers Company, New York, N.Y.

No Drawing. Continuation of application Ser. No. 685,273, Nov. 24, 1967,which is a continuation-in-part of abandoned application Ser. No.362,489, Apr. 24, 1964. This application Oct. 15, 1969, Ser. No. 866,772

Int. Cl. Clld 3/04, 3/66 U.S. C]. 252135 14 Claims ABSTRACT OF THEDISCLOSURE This application is a continuation of application Ser. No.685,273, filed Nov. 24, 1967, now abandoned, which is acontinuation-in-part of application Ser. No. 362,489, filed Apr. 24,1964, now abandoned.

The invention relates to liquid cleansing compositions and moreparticularly to an improvement in preparing stable, heavy-duty, liquiddetergent formulations.

Heavy-duty liquid detergent compositions particularly suited for laundrypurposes are well known. Many of these products tend to be unstable andtheir components separate into layers upon standing for a period oftime. This is objectionable from the consumers standpoint since measuredamounts of the detergent do not always contain the same proportion ofcleansing ingredients and the result in many instances is an inefiicientwashing performance.

Another problem in the production of heavy-duty liquid detergents isthat the viscosity of the product is not always desirable from theconsumers standpoint. Thus, the viscosity of many formulations is so lowthat the resulting product is thin and watery. In others, the viscosityis unduly excessive so that the detergent is difficult to pour.

These difficulties have, to a large extent, been obviated by thedevelopment disclosed and claimed in co-pending application Ser. No.301,957, filed Aug. 14, 1963, now abandoned. However, it has beenobserved that detergent formulations prepared by the method of Ser. No.301,957 exhibit-a gradual change in viscosity over an extended period oftime. The addition of a hydrotrope further accelerates the change in theviscosity of detergent compositions manufactured in accordance with theprocedure disclosed in said application.

It is an object of this invention to provide an improved procedure forpreparing stable, heavy-duty, liquid detergents having an acceptableviscosity and satisfactory detersive properties.

Another object is to provide phase-stable, heavy-duty liquid detergentshaving viscosities that do not change substantially with time and havingsatisfactory detersive properties.

These and other objects and advantages of the invention are attained byhydrolyzing a combination of a linear and a cross-linked copolymer ofethylene and maleic anhydride in the presence of a synthetic organicnonionic surface active agent of the polyoxyalkylene type to provide therequisite stability and viscosity to liquid detergent. compositions ofthe heavy-duty type-It is especially preferred to utilize the mixture ofcopolymers in combination with a hydrotrope to produce formulationswhich exhibit improved stability, particularly at elevated temperatures.

The products of the invention contain four ingredients which areessential and which should be employed within a specified range ofproportions if a composition having the desirable properties enumeratedabove is to be obtained. One component is water which acts as asuspending medium for the remaining ingredients in the composition.

Another necessary component is at least one nonionic synthetic non-soapdetergent of the polyoxyalkylene type used in proportions ranging fromabout 6% to about 15% based on the weight of the total formula. Thesenonionic materials are formed by condensing several moles of an alkyleneoxide such as ethylene oxide or propylene oxide with a hydrophobic basesuch as alkyl phenols, long chain aliphatic alcohols and mercaptans,propylene oxidepropylene glycol condensates, etc. Typical examples ofsuitable nonionics are shown in the following table:

TABLE I Average ethylene oxide Trade name Hydrophobe content Sterox DJDodecylphenol c. 10 moles. Sterox MJ-b n-Dodecylphenol Do. Triton X-100.0ctylphenol Do. Igepal 00-530... NonylphenoL... 6moles. Igepal (JO-730Nonylphenol 15 moles. Igepal RC520 Dodecylphenol 6 moles. Igepal RC760Dodecylphenol. 11 moles. Igepal DJ890 DinonylphenoL. percent.

Tall oil alcohoL. 9 moles. Adol 42-10E0 Unhardened tallow 10 moles.

alcohol. Alfonic 1418-6 11-C14-C1g alcohols 62.5 percent. Tergitol15S7.5 I1-C11-C15 secondary 7.5 moles.

alcohols.

Other suitable nonionics include the polyoxyethylene polyoxypropyleneethanols having the empirical formula HO (C H O),,(C H O) (C H O) Hprepared by condensing ethylene oxide with a hydrophobic base formed bythe condensation of propylene oxide with propylene glycol where b is aninteger from 26 to 30 and a plus c is an integer such that the moleculecontains from 0% to 10% ethylene oxide (Pluronic L60), or from 10% to20% ethylene oxide (Pluronic L-61).

Another critical ingredient of the heavy-duty detergents of thisinvention is at least one alkali metal pyrophosphate which should beemployed in amounts ranging from about 17% to about 35% by weight of themixture. Examples of the pyrophosphates include tetrapotassiumpyrophosphate, tetrasodium pyrophosphate, and blends of these materialsin which the tetrasodium pyrophosphate comprises up to about 20% byweight of the blend.

The remaining critical ingredient in the liquid detergents of thisinvention functions as a stabilizer to maintain the nonionic active andthe pyrophosphate components in the aqueous medium without allowingphase separation of the emulsion formed in the process. The stabilizercomprises a combination of a linear and a cross-linked copolymer ofethylene and maleic anhydride and is employed in the liquid detergent inan amount suflicient to provide both the desired stability and viscosityto the product. A suitable level of this combination of copolymersranges from about 0.60% to about 0.9% by weight of the totalcomposition.

Suitable linear copolymers of ethylene and maleic anhydride areavailable from the Monsanto Chemical Company under the designationsDX-840-21, DX-84031, BX-8404118, etc. Cross-linked copolymers areavailable under the designations DX-84061, DX-840-71, DX-84081,DX-840-91 and similar materials in this series. In general, the monomersare polymerized in a 1:1 ratio, the resins having molecular weightsranging from about 1500 and upwards. The cross-linked copolymers aregenerally cross-linked with a diamine, an alkylene polyamine, or adiolefinic material such as an ether, ester or a hydrocarbon, etc.Examples of polyamine crosslinking agents include diethylene triamine,triethylene tetramine, tetraethylene pentamine, and higher molecularweight polyethylene polyamines. Exemplary diolefinic cross-linkingagents include divinyl benzene, diallyl ether, diallyl esters and thelike. Other suitable cross-linking agents are set forth in US. Pats.Nos. 3,165,486 and 3,235,505 of Monsanto Company and include thepreferred vinyl esters of olefinically unsaturated aliphatic carboxylicacids having from 3 to 24 carbon atoms, e.g., vinyl crotonate, vinyllinoleate, divinyl itaconate, vinyl acrylate and the like. The linearand cross-linked copolymers which have been successfully utilized inpreparing formulations of this invention include the following:

Specific viscosity" l\lolccularweight Linear resin:

Determined on a 1% solution of the resin in dimethyl formamide at 25 0.

Measurements made at 25 C. on a 1% aqueous solution, adjusted to pH 9with ammonium hydroxide, using a Brookfield viscometer, No. 6 spindle at5 r.p.m.

If desired, the compositions of the invention may contain variousadditives in amounts which do not deleteriously affect the stability andpourability of the liquids. For example, the liquid detergent formulasmay contain about 2 to 10% by weight of inorganic silicate solids suchas sodium or potassium silicates.

Furthermore, hydrotropes such as methyl Carbitol and the alkali metalsalts of lower alkylaryl sulfonates may be present. The latter includesodium xylene sulfonate, sodium toluene sulfonate and mixtures thereofcontaining -25 sodium toluene sulfonate based on the combined weight ofsodium toluene sulfonate and sodium xylene sulfonate. The proportions ofhydrotrope in the formulations range from 0 to about based on the weightof the composition. Preferably, about 2% of a hydrotrope is employedbased on the weight of the total formulation.

Other suitable additives include fluorescent dyes, colorants, perfumes,germicides, bacteriostats, soil-suspending agents such as sodiumcarboxymethyl-cellulose and about 0.5 to about 3% of a suds-controllingnonionic surfactant such as the aforementioned Pluronics.

In order to provide stable, pourable and substantially homogeneousheavy-duty liquid detergents, the aforementioned necessary componentsshould be present within the range of proportions discussed above.

Moreover, the objectives of the invention can be attained mostsuccessfully by observing certain precautions in preparing theformulations of this invention.

Thus, to obtain liquid detergent products having desirable viscositiesand acceptable stability, the linear and cross-linked ethylene-maleicanhydride copolymers in substantially anhydrous form must be rapidlydispersed in an aqueous solution in the presence of the syntheticnonionic surfactant. It is preferred that the coplymers be dispersed inan aqueous solution which already contains the nonionic. However, thecopolymers and nonionic can be simultaneously dispersed in the aqueoussolution, the main requirement being that the copolymers are hydrolyzedin the presence of the nonionic component.

Preferably, the aqueous solution is at an elevated temperature toaccelerate hydration of the anhydride portion of the copolymers to theacid form in the presence of the nonionic surfactant according to thefollowing reaction:

CH2CHzCH-CH where n represents an integer. If the copolymers aredispersed in water in the absence of the nonionic surfactant, theviscosity and stability of the final composition will be adverselyaffected at the use levels recommended above.

It is preferred that the ethylene-maleic anhydride copolymers be addedto the aqueous solution of nonionic active of the polyoxyalkylene typeas rapidly as possible with stirring and heating. For best results ithas been observed that extraneous alkaline materials should not bepresent during hydration of the copolymers. After hydrolysis the pH ofthe solution should be definitely on the acid side (pH of about 2.5-3.2)to insure maximum stability.

In preparing the formulations of this invention, there are otherprecautions which must be observed, if acceptable products are to beobtained. For example, it has been found that if the copolymers are notrapidly dispersed in the aqueous mixture, the viscosity of the resultantproduct may be too low from the standpoint of preparing a commerciallyacceptable product. In general the stability is less at the lowerviscosities. The polymers, either singly or in combination, may be addedgradually to the aqueous mixture or all at once; however, each additionshould be rapidly admixed with the aqueous phase.

It is a necessary feature of the invention that the finished formula behomogenized to attain the desired stability and viscosity. The finishedproduct preferably is homogenized immediately although homogenizationmay be delayed up to about 48 hours without deleteriously affecting thecomposition. A product having optimum properties has been obtainedwithin a homogenization temperature range of room temperature to about170 F. and homogenization pressures of about 500 to about 3,000 pounds.It is obvious, however, that the conditions under which the aqueous mixis homogenized can be varied so long as the finished product hassuitable viscosity and stability characteristics. Thus, lowertemperatures can be used during homogenization if the pressure isincreased.

The following examples illustrate the preparation of compositions inaccordance with the principles of this invention. It will be understood,however, that these examples are included merely for illustrativepurposes and are not intended to limit the scope of the invention asdescribed therein unless otherwise specifically indicated.

EXAMPLE I (Basic formulation) In the following formulas Sterox DJ,Pluronic L60, Alfonic 14l86, DX-840-21 and DX-840- 61 have beenidentified above. The designations TKPP and TSPP refer to tetrapotassiumpyrophosphate and tetrasodium pyrophosphate respectively. MethylCarbitol is diethyleneglycol monomethyl ether. For all examples,laboratory size batches of about 2,000 grams were prepared.

Mixing formula for gms. of finished product Component: Gms. Distilled(zeolite) water 48.00 Sterox DJ 8.00

DX-84061 0.60 TKPP (60% soln.) 41.70

Water to balance to 100.00.

Main mixing procedure The water was heated to a temperature of about 150F. and the Sterox DJ was added with agitation. The anhydrous resins werethen added to the well-agitated mixture at a temperature of ISO-160 F.and the stirring and temperature were maintained for 1.5 hours.

At the end of this time the tetrapotassium pyrophosphate solution (60%)was slowly added while maintaining agitation at a temperature of 160170F. After a short period of mixing, the mixture was homogenized at apressure of 3,000 p.s.i.g. and at a temperature of about 153-158 F.

LEXAMPLE II Addition of hydrotrope (2%) The formulation and proceduredescribed in Example I was repeated except that 2% by weight of sodiumxylene sulfonate was fed to the aqueous phase with the necessary wateradjustment for the finished formulation. The hydrotrope (solution)preferably is added before the addition of the copolymers. A product wasobtained which had acceptable viscosity and stability characteristics.

To main mixing vessel (in order of addition) for 100 grams of finishedproduct Component: Gms. Distilled (zeolite) water 43.00 Sterox DJ 8.00Sodium xylenesulfonate (40%) 5.00 DX-840-21 0.20 DX-8406l 0.60 TKPP (60%soln.) 41.70 Water to balance to 100.00.

EXAMPLE III (1% Pluronic L60+2% hydrotrope) The formulation andprocedure described in Example II was repeated except that 1% by Weightof Pluronic L-60 was added to the aqueous phase with the necessaryadjustment for the finished formulation. In accordance with thepreferred procedure, the Pluronic IP60 was added before the resins.

To main mixing vessel (in order of addition) for 100 grams of finishedproduct Component: Gms. Distilled (zeolite) water 42.00 Sterox DJ 8.00Sodium xylenesulfonate (40%) 5.00 Pluronic L-60 1.00 DX84021 0.20DX-840-61 0.60 TKPP (60% soln.) 41.70 Water to balance to 100.00.

EXAMPLE IV Addition of fluorescent dye and methyl carbitol to theformulation in Example III with necessary water adjustment.

Mixing formula for 100 grams of finished product 6 Mix No. II(containing Mix No. I) 8.21 Pluronic L-60 1.00 Sodium xylenesulfonate(40% soln.) 5.00 DX84021 0.20 DX-840-6l 0.60 TKPP (60% soln.) 41.70 MixNo. II 0.67

Water to balance to 100.00.

Mixing procedure Mix No. I.The methyl Carbitol was heated to about190200 F. with agitation. The fluorescent dye was then added andagitation continued until dispersion was substantially complete. Mixingwas continued and the temperature maintained at 190-200 F. until readyfor use.

Mix No. II.The Sterox DI was heated to F. Mix No. 'I was added withagitation and maintained at this temperature with continued agitationuntil ready for use.

Mix. No. III.The methyl Carbitol was heated to a temperature of 190200F. with agitation until dispersion was complete. Mixing was continuedand the above temperature maintained until the mix was ready for use.

Main mixing procedure The water was heated to a temperature of about F.and Premix No. II (which contained Premix No. I) was added withagitation. The Pluronic L-60 was then added followed by the sodiumxylenesulfonate. Then the anhydrous resins were rapidly added to thewellagitated mixture while maintaining the temperature at ISO- F. for1.5 hours.

At the end of this time the tetrapotassium pyrophosphate solution (60%)was slowly added while maintaining agitation and a temperature ofl60-170 F. This was followed by the addition of Mix No. III and theentire reaction mixture was agitated at 160-170 F. for an additional 10minutes. The mixture was homogenized at a pressure of 3,000 p.s.i.g. anda temperature of about 153-l58 F.

EXAMPLE V Addition of sodium silicate and potassium hydroxide to theformulation in Example IV with the necessary water adjustment.

To main mixing vessel (in order of addition) Distilled (zeolite) water3000 Mix No. II (containing Mix No. I)

8.21 Pluronic L-60 1.00 Sodium Xylenesulfonate (40% soln.) 5.00DX-840-21 0.20 DX-840-6l 0.60 TKPP (60% soln.) 41.70 Potassium hydroxide(45.5%) 1.80 Sodium silicate (37.0% solids; 1:25 ratio of Na O:SiO 8.10Water to balance to 100.00.

. EXAMPLE VI Addition of sodium carboxymethylcellulose, colorant andsubstitution of 8:1-TKPP2TSPP for TKPP in the formulation in Example Vwith the necessary water adjustment.

Mixing formula for 100 grams of finished product Mix No. I: Gms. MethylCarbitol 0.195 Fluorescent dye 0.015

Mix No. II:

Sterox DJ 8.00 Mix No. I 0.21

Mix No. III:

Methyl Carbitol 0.575 Fluorescent dye 0.096 Colorant 0.025

To main mixing vessel (in order of addition) Distilled (zeolite) water28.00

Mix No. II (containing Mix No. I) 8.21

Pluronic L-60 1.00

Sodium xylenesulfonate (40% soln.) 5.00

8:1-TKPP1TSPP (55% soln.) 45.45

Potassium hydroxide (45.5%) 2.00

Sodium silicate (37.0% solids; 1:2.5 ratio of Na O:SiO 8.10

Sodium carboxymethylcellulose (75%) 0.50

Mix No. III 0.6

Perfume 0.10

Water to balance to 100.00.

EXAMPLE VII Increased level of TKPP (35%) and use of Alfonic 1418-6 asthe nonionic.

Mixing formula for 100 grams of finished product Mix No. I: Gms. MethylCarbitol 0.195 Fluorescent dye 0.015

Mix No. II:

Alfonic 1418-6 8.00 Mix No. I 0.21

Mix No. III:

Methyl Carbitol 0.595 Fluorescent dye 0.295 Colorant 0.025

To main mixing vessel (in order of addition) Distilled (zeolite) Water27.50

Sodium xylenesulfonate (40%) 5.00 Mix No. II (containing Mix No. I) 8.21Pluronic IP60 1.00 DX-840-21 0.20

DX84061 0.60 TKPP (60/soln.) 58.50 KOH (45.5% soln.) 1.80 Sodiumsilicate (37.0% solids; 1:2.5 ratio of Na O:SiO 8.10 Sodiumcarboxymethylcellulose (75% active) 0.50 Mix No. III 0.915 Perfume 0.10Water to balance to 100.00.

EXAMPLE VIII Combination of 0.1% DX8404118 (linear) and 0.5% DX84061(cross-linked) resins Mixing formula for 100 grams of finished productMix No. I: Gms. Methyl Carbitol 0.195 Fluorescent dye 0.015

Mix No. II:

Sterox DJ 8.00 Mix No. I 0.21 Mix No. III:

8 Methyl Carbitol 0.575 Fluorescent dye 0.307 Colorant 0.025

Water 0.500

To main mixing vessel (in order of addition) Distilled (zeolite) water27.50

Sodium xylenesulfonate (40%) 5.00 Mix No. II (containing Mix No. I) 8.21Pluronic L-60 1.00

DX-840-61 0.50 TKPPzTSPP (8:1 ratio, 55% solids) 45.45 KOH (45.5% soln.)1.80 Sodium silicate (37.0% solids; 1:2.5 ratio of Na O:SiO 8.10 Sodiumcarboxymethylcellulose (75% active) 0.50 Mix No. III 1.407

Perfume 0.10 Water to balance to 100.00.

EXAMPLE IX Combination of 0.20% DX840-21 (linear) and 0.5% DX-840-91(cross-linked) resins Mixing formula for grams of finished product MixNo. I: Gms. Methyl Carbitol 0.195 Fluorescent dye 0.015

Mix No. II:

Sterox DJ 8.00 Mix No. I 0.21

Mix No. III:

Methyl Carbitol 0.575

Fluorescent dye 0.095

Colorant 0.025

To main mixing vessel (in order of addition) Distilled (zeolite) water28.00

Sodium xylenesulfonate (40%) 5.00

Mix No. II (containing Mix No. I) 8.21

Pluronic L-60 1.00

TKPP:TSPP (8:1 ratio, 55% soln.) 45.45

KOH (45.5% soln.) 1.50 Sodium silicate (37.0% solids; 1:2.5 ratio of NaOZSiO Sodium carboxymethylcellulose (75 active) 0.50 Mix No. III 0.695Perfume 0.10

Water to balance to 100.00.

The properties of phase stability and viscosity stability over extendedstorage periods are readily demonstrated by comparing representativeproducts prepared according to the procedure in Example VI above withsimilar products prepared by the same procedure but having only onestabilizing resin in place of the combination of resins as shown by thecomparative data in Table II below.

Phase stability was determined by storing the products at roomtemperature (R.T.) and recording the time for a 5% rise or separationtherein. Phase stability was also determined by an accelerated phasestability test wherein a sample of the detergent emulsion compositionwas placed in a centrifuge tube and the tube inserted into a centrifugewhich was then rotated for 30 minutes at 5,000 r.p.m. which isequivalent to a centrifugal force of about 5,000 g. The percent phaseseparation was then recorded. The apparent viscosity measurements weremade using a Brookfield LVF Viscometer, No. 3 spindle, at 30 r.p.m. for30 seconds at room temperature (7880 E).

Representative Formulations Nos. and K of the invention were markedlysuperior to comparative Formulations CNos. A, B, H and J in both phasesite ratios of linear to cross-linked resin may depend to some extent onthe respective molecular weights and on the degree of cross-linkinginvolved. However, the judicious selection of the ratio of linear tocross-linked resin will provide liquid detergent compositions whoseviscosities do not change substantially on standing for relatively longperiods of time. The weight ratio of linear copolymer to cross-linkedcopolymer is generally from about 1:6 to about 3 :1 and more usuallyfrom about 1:3 to about 1:1.

Moreover, the invention is not limited to liquid detergent compositionshaving a particular viscosity value. While the consumer generallydesires a thickened product, preferences for thinner compositions areoccasionally expressed and the present invention offers an improvedprocedure for providing a wide range of detergent viscosities.

It will be appreciated that various modifications and changes may bemade in the liquid detergent compositions and method of the invention inaddition to those discussed and illustrated above without departing fromthe spirit of the invention and accordingly the invention is to belimited only within the scope of the appended claims.

What is claimed is:

1. A method for the preparation of a phase-stable, pourable, heavy-duty,liquid detergent emulsion composition which does not exhibit asubstantial change in viscosit'y on standing comprising:

40 (a) rapidly admixing a first stabilizer which is a linear copolymerof ethylene and maleic anhydride having a specific viscosity of fromabout 0.6 to about 1.8%

with a hydrophobic base selected from the group consisting of higheralkyl phenols and alcohols in order to hydrolyze the two stabilizers tothe acid form and thereby provide a mixture having a pH of from about2.5 to about 3.2;

(b) blending the resultant mixture with at least one alkali metalpyrophosphate selected from the group consisting of tetrapotassiumpyrophosphate, tetrasodium pyrophosphate and blends of these materialsin which the tetrasodium pyrophosphate comprises up to about 20% byWeight of the blend; and (c) homogenizing the aqueous mixture; theamounts of said stabilizers, nonionic synthetic detergent, pyrophosphateand water based on the weight of the composition being from about 0.6%to about 0.9% total of the two stabilizers, from about 6% to about 15%of the nonionic synthetic detergent, from about 17% to about 35% of thealkali metal pyrophosphate and the balance substantially water; theWeight ratio of said first stabilizer to said second stabilizer beingfrom about 1:6 to about 3:1. 2. The method according to claim 1 whereinfrom about 2% to about 10% based on the weight of the com- 75 positionof an alkali metal silicate selected from the Z a 3+ as as ea 2 .E 2-fi-.----....HHHHmHHHHHHHHHHHM o a 6 25+ g H 8n 5 w d m. h o 3 ga i 2:8m 2m wd w Q a. 55 2am 5-833 HNAE NQ 263mm 2.63am 92 a E... as 2 .mm e-m. @.-.-.::.HHHHnHHHnHHHHHHHHM 98 wm+ 9; H Q3 Q6 wb in 2 ga 2: Se wd we a $5 r m S QETMQ HTEW NQ 586M uswocwm 3 8 5T 5 as w a fie rnuHHHHHHHHHHHHHHHH a em al 0% m8 we 18 H 93o one m em mi e 8e we 13 H 50 5 0 m 9m 8 as 2m 3m @5 1m 5 c 5 o so 24+ m8 5 we mm 2. We o 5 e um 8m8m e o mb o 2 ga c5 wd w o 4 cosfi mm m weB he on w a w m m H z weomrv 22m 23% SIQMTNQ Eww vmfi 2 2 02:3 ammwwiw m m WSMQQME mm m R m wfimfianna -38 53mm 596k m 3 ABEPE 083 a 638 z moowg nfiwan w H235 252mm35 5 ousouw HS. HAMWQB 1 1 group consisting of sodium and potassiumsilicates is added after the pyrophosphate.

3. The method according to claim 1 wherein from about to about 5% basedon the weight of the composition of a hydrotrope selected from the groupconsisting of diethylene glycol monomethylether, sodium xylenesulfonate, sodium toluene sulfonate and mixtures thereof containing 025%sodium toluene sulfonate based on the combined weight of sodium toluenesulfonate and sodium xylene sulfonate is present in said aqueous mixtureprior to the addition of said stabilizers.

4. The method according to claim 1 wherein the nonionic syntheticdetergent is a condensate of dodecyl phenol with from 6 to 11 moles ofethylene oxide.

5. The method according to claim 1 wherein the aqueous mixture ismaintained at an elevated temperature of from about 150 F. to about 160F. during the blending of the two stabilizers therewith.

6. The method according to claim 1 wherein the homogenizing is conductedat from room temperature at about 170 F. and at a pressure from about500 to about 3,000 p.s.i.g.

7. The method according to claim 1 wherein about 0.5% based on theweight of the composition of sodium carboxymethyl cellulose is addedafter the silicate.

8. The method according to claim 1 wherein the weight ratio of saidfirst stabilizer to said second stabilizer is from about 1:3 to about1:1.

9. A phase-stable, pourable, heavy duty liquid detergent emulsioncomposition which does not exhibit a substantial change in viscosity onstanding consisting essentially of from about 6% to about 15% by weightof at least one nonionic synthetic detergent condensate of an alkyleneoxide with a hydrophobic base selected from the group consisting ofhigher alkyl phenols and alcohols; from about 17% to about 35% by weightof at least one alkali metal pyrophosphate selected from the group con-Sisting of tetrapotassium pyrophosphate, tetrasodium pyrophosphate andblends of these materials in which the tetrasodium pyrophosphatecomprises up to 20% by weight of the blend; from about 0.6% to about0.9% by weight of a combination of a first stabilizer which is ahydrolyzed linear copolymer of ethylene and maleic anhydride having aspecific viscosity of from about 0.6 to about 1.8 and a secondstabilizer which is a hydrolyzed copolymer of ethylene and maleicanhydride cross-linked with a vinyl ester of an olefinically unsaturatedaliphatic carboxylic acid having from 3 to 24 carbon atoms, saidcopolymer having a viscosity of from about 12,000 centipoises to about160,000 centipoises; and the balance substantially water; the weightratio of said first stabilizer to said second stabilizer being fromabout 1:6 to about 3:1.

10. The composition according to claim 9 which also contains from about2% to about 10% by weight of an alkali metal silicate selected from thegroup consisting of sodium and potassium silicates.

11. The composition according to claim 9 which also contains from about0% to about 5% by weight of a hydrotrope selected from the groupconsisting of diethylene glycol monomethylether, sodium xylenesulfonate, sodium toluene sulfonate, and mixtures thereof containing0-25% sodium toluene sulfonate based on the combined weight of sodiumtoluene 'sulfonate and sodium xylene sulfonate.

12. The composition according to claim 9 which also contains about 0.5by weight of sodium carboxymethyl cellulose.

13. The composition according to claim 9 wherein the Weight ratio ofsaid first stabilizer to said second stabilizer is from about 1:3 toabout 1:1.

14. The composition according to claim 9 wherein the cross-linking agentis vinyl crotonate.

References Cited UNITED STATES PATENTS 2/1966 Tuvell 252 5/1967 Grifo etal 252-137 US. Cl. X.R. 252-138. 161

